On Fri, Feb 6, 2015 at 6:58 PM, IVP wrote: > They mention low voltage lighting, which I assumed to be halogens > and transformers rather than LEDs > > Your LED load is quite large, compared with what most people > would experience, but it probably isn't quite enough to justify an > IGBT although I'm sure an IGBT would work Agreed. I didn't see a reason not to use an IGBT (other than the timing we mentioned earlier), but I didn't see a reason TO use one either. > It was a suggestion in case you had problems with the wiring such > as switching transients etc that can be an issue for FETs which don't > have enough protection. In the worst-case scenario you could be > PWMing a lot of current into "some" inductance. Destructive noise > can also be induced onto long wiring from external sources too, and > it might be an idea to consider a sprinkling of remote ultrafast diodes > (anti-parallel to the LEDs) as well as the local Schottkys and zeners > protecting the FETs Ah, I gotcha. At the moment I haven't gotten very far in the design, so I haven't done the protection side yet. The part I'm currently looking at (https://www.fairchildsemi.com/datasheets/FD/FDD8647L.pdf) does have a built in DS diode. I'm guessing adding an external as well wouldn't be a bad idea. Do you think a GS diode is needed as well? So far the only design guides I've found are from the diode manufacturers. I'd love to see something from Fairchild about what they think their products need. Still searching... Josh --=20 A common mistake that people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools. -Douglas Adams --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .